Systems for and methods of assigning priority to reader antennae

ABSTRACT

Methods, systems, and articles of manufacture for assigning priority to antennae are disclosed. In accordance with a preferred embodiment of the invention, reader antennae identify the location of an object by detecting a tag or other identifier associated with each object. Sensors can be provided to provide additional information regarding the environment of the objects or their surroundings. A priority order is assigned to the reader antennae based on the location and other characteristics of the objects and/or their environment. A polling sequence for reading the reader antennae is determined according to the priority order.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of pending U.S. non-provisional patentapplication Ser. No. 10/586,190, filed Aug. 11, 2008, which is anational stage entry of International Application No. PCT/US2005/001259,filed Jan. 25, 2005, which claims priority to U.S. ProvisionalApplication No. 60/536,703, filed Jan. 16, 2004, the entirety of whichapplications are hereby incorporated by referenced in their entirety.

BACKGROUND

Radio frequency identification (RFID) systems typically use one or moreRFID reader antennae to send radio frequency (RF) signals to itemstagged with RFID tags. The use of such RFID tags to identify an item orperson is well known in the art. In response to the radio frequency (RF)signals from an RFID reader antenna, the RFID tags, when excited,produce a disturbance in the magnetic field (or electric field) that isdetected by the RFID reader antenna. Typically, such tags are passivetags that are excited or resonate in response to the RF signal from anRFID reader antenna when the tags are within the detection range of theRFID reader antenna.

The detection range of the RFID systems is typically limited by signalstrength to short ranges, for example, frequently less than about onefoot for 13.56 MHz systems. Therefore, portable reader units may bemoved past a group of tagged items in order to detect all the taggeditems, particularly where the tagged items are stored in a spacesignificantly greater than the detection range of a stationary or fixedsingle RFID reader antenna. Alternately, a large RFID reader antennawith sufficient power and range to detect a larger number of taggeditems may be used. However, such an antenna may be unwieldy and mayincrease the range of radiated power beyond allowable limits.Furthermore, these RFID reader antennae are often located in stores orother locations where space is at a premium and it is expensive andinconvenient to use such large RFID reader antennae. In another possiblesolution, multiple small antennae may be used but such a configurationmay be awkward to set us when space is at a premium and when wiring ispreferred to be hidden.

Current RFID reader antennae are designed so that a sufficient readrange maybe maintained between the antenna and associated tags, withoutrunning afoul of FCC limitations on radiated emissions.

Resonant RFID reader antenna systems are currently utilized in RFIDapplications, where numerous RFID reader antennae are connected to asingle reader. Each RFID reader antenna may have its own tuning circuitthat is used to match to the system's characteristic impedance. An RFIDreader or interrogator maybe connected to more than one antenna, forexample, to save cost or complexity of using many readers, particularlyif a fast read rate is not necessary. However, sharing a reader meansthat a given antenna may not be read as often. It may be desired,however, to know immediately when an item is removed from the vicinityof an antenna, or at least to monitor the antenna for a time thereafter.It may therefore be useful to develop methods that allow the RFID readerto prioritize the order in which antennae are read.

SUMMARY

Methods, systems, and articles of manufacture for assigning priority toantennae are disclosed. In accordance with a preferred embodiment of theinvention, reader antennae identify the location of an object bydetecting a tag or other identifier associated with each object. Sensorscan be provided to provide additional information regarding theenvironment of the objects or their surroundings. A priority order isassigned to the reader antennae based on the location and othercharacteristics of the objects and/or their environment. A pollingsequence for reading the reader antennae is determined according to thepriority order.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram depicting an exemplary system in accordancewith a preferred embodiment of the invention; and

FIGS. 2A-2B illustrate exemplary steps of assigning priority to readerantennae in accordance with a preferred embodiment of the invention.

DETAILED DESCRIPTION

Preferred embodiments and applications of the invention will now bedescribed. Other embodiments may be realized and changes may be made tothe disclosed embodiments without departing from the spirit or scope ofthe invention. Although the preferred embodiments disclosed herein havebeen particularly described as applied to the field of RFID systems, itshould be readily apparent that the invention may be embodied in anytechnology having the same or similar problems. Furthermore, while theexamples herein are particularly described in relation to a shelfsystem, for example, in a facility such as a retail store, it should bereadily apparent that the invention may be embodied in other forms andin other facilities.

An exemplary embodiment of the invention may be implemented in AntennaPrioritization System 100 as illustrated in FIG. 1. The exemplaryAntenna Prioritization System 100 preferably includes a Controller 110coupled to a Local Database 115, a Reader 140, and User InterfaceDevices 130. In this embodiment, Controller 110 may include one or morecentral processing units (CPUs) or other calculating or processingdevices to provide processing of input/output data between AntennaPrioritization System 100, Network 160, Local Database 115, a Reader140, and User Interface Devices 130.

Preferably, Controller 110 executes one or more computer-executableprograms stored in memory (e.g., Local Database 115, etc.). LocalDatabase 115 can include one or more memory devices comprising anyrecordable or rewritable medium for storing information (e.g., harddrive, flash RAM, optical disc, compact disc, memory card, DVD, etc.).User Interface Devices 130 include any device that can be used to enterinformation (e.g., commands, data, etc.) into Controller 110 (e.g.,keyboard, touch screen, wireless device, PDA, infrared device, radiofrequency device, etc.).

In a preferred embodiment of the invention, Antenna PrioritizationSystem 100 may further include Reader 140. Reader 140 can be used tointerrogate, read, or otherwise activate one or more reader antennae(e.g., Reader Antenna 151-153) coupled to Reader 140. In this exemplaryimplementation, Reader Antennae 151-153 are incorporated in shelf 105and may include tuning circuitry as described in U.S. patent applicationSer. No. 10/338,892, which is incorporated herein by reference in itsentirety. Reader 140 transmits the information obtained from ReaderAntenna 151-153 to Controller 110 in a manner well known in the art.

In a preferred embodiment, Reader Antenna 151-153 are preferably RFIDreader antennae capable of generating radio frequency waves 50. Theradio frequency waves interact with RFID tags 60 which can be affixedto, integrated with, or otherwise coupled to an object (e.g., product,employee, customer, etc.). An RFID tag 60, when excited by radiofrequency waves 50, produces a disturbance in the magnetic field (orelectric field) that is detected by RFID reader antennae. Preferably,reader 140 may be instructed by Controller 110, for example, tointerrogate, read, or otherwise activate one or more reader antennae(e.g., Reader Antennae 151-153) according to a priority order in aparticular polling sequence. For example, Controller 110 may instructReader 140 to interrogate Reader Antennae 151-153 by reading ReaderAntenna 153 followed by Reader Antenna 152 followed by Reader Antenna151. As discussed herein, in accordance with a preferred embodiment ofthe invention, the priority order can be assigned based on the locationof Item 70 or Customer 80 (e.g., the proximity of Item 70 or Customer 80to Reader Antenna 152, etc.).

In accordance with a preferred embodiment of the invention, the readerantennae may be affixed to a mobile or stationary object. As depicted inthe exemplary implementation of FIG. 1, Reader Antennae 151-153 areaffixed to a product support structure such as Shelf 105. ReaderAntennae 151-153 can be used to communicate by, for example, radiofrequency waves 50 with RHD tags such as RFID 60, shown attached to item70. In accordance with a preferred embodiment, sensors are utilized(e.g., affixed to a mobile or stationary object, etc.) to provideadditional information regarding the environment of objects beingmonitored or their surroundings. In this exemplary implementation,Sensors 121-123 are affixed to Shelf 105 and provide additionalinformation to Controller 110. Sensors 121-123 can include weightsensors, vibration sensors, pressure sensors, pushbutton sensors,infrared sensors, optical sensors, audio sensors, etc. In a preferredembodiment, other sensing signals 85 can provide additional informationto Controller 110 which can be combined information from Sensors 121-123or independently provided to Controller 110. In accordance with apreferred embodiment of the invention, the information provided bysensors can be used to affect the priority assigned to different readerantennae as described herein.

Antenna Prioritization System 100 may be connected directly orindirectly (e.g., through network 160, as shown in FIG. 1) to one ormore Remote Applications 170 coupled to Main Database 180. Network 160may represent any type of communication configuration that allowsAntenna Prioritization System 100 and Remote Application 170 to exchangeinformation. For example, network 160 may be a Local Area Network (LAN),a Wide Area Network (WAN), Bluetooth™, and/or a combination of networks,such as the Internet. Network 160 may also include the infrastructurethat allows Antenna Prioritization System 100 and remote application 170to exchange information using wireless based communications.

Preferably, Local Database 115 and Main Database 180, in each instance,may include one or more storage device systems (e.g., internal harddrive, external hard drive, flash RAM, ROM, memory card, and opticaldisk, etc.) that store information (e.g., computer executable programs,data regarding products and/or facilities, etc.) used by AntennaPrioritization System 100 and/or Remote Application 170. The term“database” can refer to the means for storage of more than one datafile, computer executable program, or table. In a preferred embodiment,Local Database 115 and/or Main Database 180 may comprise more than onedatabase or a series of databases housed locally or in a remotelocation. Such databases may be controlled, for example, by a databaseserver (not shown), such as an SQL database server. A Java DataBaseConnectivity (JDBC) driver for the SQL server may also be used to accessthe SQL server database. Local Database 115 and/or Main Database 180 maybe embodied within Antenna Prioritization System 100, or external toAntenna Prioritization System 100, for example, on a server (not shown).Furthermore, Local Database 115 and/or Main Database 180 may be sharedwith more than one Antenna Prioritization System 100.

In accordance with a preferred embodiment, Local Database 115 and/orMain Database 180 may be used to store item or object information (e.g.,identification information regarding an item such as Stock Keeping Unit(SKU) data, etc.). The SKU information may include item type,manufacturer and origin, size, color, style, as well as a wide varietyof other types of information that are understood by those skilled inthe art. Such item information may be stored, for example, in tablesmaintained on Local Database 115 and/or Main Database 180 or in a remoteor local database or system. Examples of item information include, butare not limited to:

(1) A Uniform Product Code (UPC) and/or an Electronic ProductIdentification Code (EPIC). It should be understood that items made by acertain manufacturer in a certain size, color, etc. may have all thesame UPC but each may have a unique EPIC;

(2) Current price of the item;

(3) Seasonality of the item. A seasonality indicator may represent arelationship between an item and a period of time associated withdifferent events or seasons, such as holidays, a time frame surroundinga certain date of a special event (e.g., the Super Bowl), etc. Forexample, a soap product may have a seasonality indicator representing noseasonal characteristics, such as “no season,” wreaths may have a“Christmas” indicator, charcoal may have a “summer” indicator, etc.Further, promotional items (e.g., those items that are being speciallymarketed by a manufacturer or retailer) may have a seasonality indicatorassociated with a time frame (e.g., “July 2003”). The seasonalityindicators may be used to determine when to remove or restock certainitems in inventory; and

(4) Shelf life of the item. The term “shelf life” can refer to a periodof time that an item may be allowed to be included in inventory. Forexample, perishable products, such as milk, may have a limited period oftime that they may be presented on a shelf for sale to a customer.Non-perishable products may also have a limited period of time to bepresent in inventory based on one or more factors, such as previoussales of items of a similar type, limited promotional time frames, etc.

Additionally, for an item collection of a certain type (e.g., anindividual box of any type of item), examples of stored item informationinclude, but are not limited to, the following:

(1) The EPIC of the item;

(2) The UPC of the item which can be associated with the SKU informationdescribed above;

(3) Other types of information not directly known from the SKU (e.g.,color, style, size, etc.);

(4) A serial number associated with the item (if other than the EPIC);

(5) A cost of the item to a business entity associated with its use,such as a retailer;

(6) A date the item was first placed in a particular location orlocations;

(7) The expiration date of the item (if any);

(8) Item location information representing a current physical locationof the item (or if sold, the last known location of the item);

(9) The price at which an item was sold (if already sold);

(10) The date the item was sold (if already sold);

(11) The preferred customer number of a purchaser (if already sold)representing a unique number assigned to a user that purchases or maypurchase items; and

(12) A unique serial number associated with the RFID tag 60, forexample, an identification number written to the RFID tag 60 by itsmanufacturer.

One skilled in the art will appreciate that the above examples of iteminformation are not intended to be limiting. Local Database 115 and/orMain Database 180 may include more or fewer tables or otherconfigurations of item information used by Remote Application 170 and/orAntenna Prioritization System 100. Some or all of the information inMain Database 180 may also be stored in Local Database 115.

In accordance with a preferred embodiment, the priority order can bedetermined in a variety of manners influenced by a variety of factors(e.g., data derived from sensors, reader antennae, historical data,marketing data, etc.). The term “priority order” refers to a relativepositioning or arranging of objects (e.g., reader antennae, fixtures,objects, etc.) in an ordered sequence. The term “priority order” mayalso refer to a length of time to be spent (e.g., monitoring) on a givenobject. The term “predetermined criteria” refers to a factor or factorsthat differentiate the characteristics of one object from anotherobject. For example, objects can be arranged in a priority orderaccording to predetermined criteria (e.g., weight, size, density, etc.).In this example, heavier objects have a higher priority with respect tolighter objects. Thus, in this exemplary priority order, objects arearranged in a priority order from the heaviest object to the lightestobject. An object that is assigned a higher “priority” or “level” in thepriority order can, for example, have a higher position in a priorityorder compared to an object assigned a “lower” priority or “level.”

An object that is assigned a higher level in a priority order is alsosaid to have a higher preference level than objects at lower levels inthe priority order. The term “preference level” refers to the relativevalue assigned to an object compared to other objects in a group orgroups of objects, In one preferred embodiment of the invention,preference levels can be assigned to objects according to any givenbasis (e.g., predetermined criteria, randomly, equal frequency, etc.). Apriority order can then be arranged by comparing the preference levelsassigned to various objects, and a priority order can be determined byarranging the objects according to their preference levels (e.g., fromhighest to lowest, lowest to highest, etc.). For example, a priorityorder can be arranged for 100 objects with each object being assigned amutually exclusive preference level from 1-100. In this example, anobject with a preference level of 1 will have the highest priority inthe priority order, while an object with a preference level of 100 willhave the lowest priority in the priority order. After the preferencelevels of the 100 objects have been assigned, they can be arranged in anexemplary priority order from 1-100. (To the extent preference levelsare not assigned on a mutually exclusive basis, relative priority ofobjects may be assigned arbitrarily or using any other additionalbasis.)

In a preferred embodiment of the invention, the priority order can bearranged without reference to preference levels. For example, a priorityorder can be arranged randomly, according to predetermined timeschedule, or any other suitable factor. In another preferred embodimentof the invention, a priority order can be arranged according to multiplepredetermined criteria. For example, objects can be arranged accordingto both their size and weight. The term “object” refers to any tangibleitem capable of being detected (e.g:, customer, a product, a basket, acart, etc.). An object can be associated, for example, with an RFID tagor another identifying tag. The term “predetermined criteria” refers toa factor or factors that differentiate the characteristics of one objectfrom another object. For example, objects can be arranged in a priorityorder according to predetermined criteria (e.g., weight, size, density,etc.). For example, heavier objects can have a higher priority withrespect to lighter objects. Thus, in this exemplary priority order,objects are arranged in a priority order from the heaviest object to thelightest object. An object that is assigned a higher “priority” or“level” in the priority order can, for example, have a higher positionin a priority order compared to an object assigned a “lower” priority or“level.” Predetermined criteria can also be weighted with respect toeach other. Thus, the weight of an object can influence its position ina priority order twice as much as its size.

In a preferred embodiment of the invention, a first reader antennahaving a higher preference level is assigned a higher priority than atleast a second reader antenna having a lower priority. In thisembodiment, a preference level is assigned to each antenna and theantennae are arranged in a priority order according to their relativepreference levels. An antenna with higher preference level has acorresponding higher priority than an antenna with a lower preferencelevel.

In a further preferred embodiment of the invention, reader antennae areread or interrogated according to their priority order. Thus, an antennahaving a higher priority (e.g., based on being assigned a higherpreference level) is read or interrogated before an antenna having alower priority (e.g., having a corresponding lower preference level).

In another preferred embodiment of the invention, preference levels canbe assigned according to the object or objects detected by each of theplurality of reader antennae. For example, the presence of a particularproduct having an identifying tag may result in a higher preferencelevel assigned to the corresponding antenna. Assignment of a higherpreference level of an antenna may result in being assigned a higherposition in a priority order. A store manager, for example, may want toclosely monitor the stock of a particularly popular item in order toprovide accurate and up to date information regarding the supply tocustomers. In another preferred embodiment, a first reader antenna thatdetects a larger number of products is assigned a higher preferencelevel than at least a second reader antenna that detects a smallernumber of products.

In another preferred embodiment of the invention, a probability that adetected product will be moved from a predetermined location can be usedas predetermined criteria for assigning preference levels (or otherwisesetting priority order). The probability that a product will be movedcan be determined in a variety of ways. It can be, for example,calculated by detecting movement frequency of the plurality of productsfrom a predetermined location during a predetermined fine interval andcalculating the average movement frequency of the plurality of productsfrom the predetermined location during the predetermined time interval.In a preferred embodiment, a preference level can be assigned to each ofthe plurality of reader antennae according to the probability the objectwill be moved. In this example, a higher preference level corresponds toa higher position in a priority order. Using this preferred embodimentof the invention, a store manager can calculate the number of popularitems moved from a particular shelf in an hour to determine how manyitems need to be replaced.

In another preferred embodiment, the preference level can be assignedaccording to a preference factor. The term “preference factor” refers topredetermined criteria used to assign a preference level to an object.Preference factors can include, but are not limited to, movement of anidentifying tag associated with a reading antenna, proximity of acustomer to a reader antenna, proximity of an employee to a readingantenna, and proximity of a product to a reading antenna. For example,if an identifying tag or group of identifying tags is moved out of therange of a reader antenna, the reader antenna can be assigned a higherpreference level than an antenna where identifying tags have not beenmoved. A priority order can be arranged according to, for example,frequency of identifying tag movement where increased movement ofidentifying tags corresponds to a higher priority than decreased or nomovement of identifying tags.

In another preferred embodiment of the invention, preference levels orpriority order can be assigned based on a triggering event or input datafrom a device such as a computer server, a computer workstation, ahandheld device, a telephone, a wireless device, etc. In this example,priority can be assigned manually or according to a time interval. Thus,a store manager or a company manager located in a remote location caninterrogate a reader antenna e.g., associated with a particular shelf tomonitor the movement of a popular item at a particular time of day orduring an important time period (e.g., Christmas shopping season).

In another preferred embodiment of the invention, preference levels orpriority order can be assigned to reader antennae based on input datafrom a sensor. For example, a sensor may be an optical sensor, avibration sensor, an audio sensor, a pressure sensor, a pushbuttonsensor, etc., indicating an event (e.g., the presence or absence of acustomer, employee, particular product, etc.). The sensor can be used toassign a preference level to reader antennae. For example, if a sensordetects the presence of a customer, the antenna associated with thesensor can be assigned a higher preference level and a correspondinghigher position in a priority order than an antenna that is notassociated with the presence of customer.

In a preferred embodiment of the invention, the priority order can bestored in a table (e.g., in Local Database 115) for use (e.g., byController 110) in determining a polling sequence for interrogatingreader antennae. The term “polling sequence” refers to the order (orlength of time) in which reader antenna are read or interrogated. Thepolling sequence can be arranged according the priority order,preference levels, or any other suitable factor or factors.

Preferred embodiments of the invention and the steps for assigningpreference levels to reader antennae, determining a priority order,and/or determining a polling sequence can be embodied in a computerexecutable medium stored in a computer readable medium (e.g., harddrive, flash drive, memory card, RAM, ROM, DVD, CD, optical disc, etc.).The computer readable medium can be used in, for example, Controller 110according to preferred embodiments of the invention described herein.

In an exemplary implementation of a preferred embodiment of theinvention, the priority order is equal to the summation of individualfactors that may be weighted according to predetermined criteria as setforth below:

Read Priority=Σ_(t=1) ^(n) Xim×wim

where P_(m)=Read Priority for antenna m

n=Number of rules for prioritization

X_(im)=ith priority factor associated with mth antenna

wim=ith weighting factor associated with mth antenna

In one application of this exemplary implementation, for example, eachantenna is assigned a preference level based on how often the inventoryof tagged objects or items inside the antenna's range is moved. Forexample, let t_(i) be the time of read event i. The term “event” in thisexample preferably refers to a change in inventory (e.g., increase,decrease, change to the identifying tag, etc.). For example, thedisappearance of a tagged item from the range of an antenna is definedas a read event since the event is viewed by the antennae as a change ininventory. In this implementation, the priority order can be defined asfollows:

t−t_(i) is the elapsed time since read event i;

α and β are constants;

Let Φ_(i)=α+(t−t _(i)) or Φ_(i)=α+β(t−t _(i))

At the moment read event i occurs, Φ is defined and has a value of α. Astime continues the value of Φ_(i) grows linearly. The priority valueγ_(m) for antenna m is defined as:

γm≡Σ_(i-1) ^(Nm) exp {−Φi} where N_(m) is the total number of readevents on record for the antenna m. Preferably, user-defined criteriamay be defined to limit the number N_(m). For example, N_(m) might onlyinclude events within the last hour, last 15 minutes, or other timespan, or only the most recent 10 events for each antenna.

In this preferred implementation, γ_(m) will be largest for antennaewith a large number of recent read events. Antennae can receive a readpriority from largest γ_(m) to smallest γ_(m). Other formulas may alsobe used for γ_(m). For example,

${\gamma \; m} \equiv {\sum\limits_{i - 1}^{Nm}\left( \frac{1}{\Phi_{i}} \right)}$

where, if a large time interval elapses without reading a particularantenna, greater priority may be placed on reading that antenna. Forexample, a function ε could be defined as

ε=δ(t−t_(last)) where t_(last) is the time of the last read event and δis a constant. The read priority for an antenna can be based on the sumof c and γ_(m). In this example, the equation will balance the need toread some antennae more frequently with the need to read all antennaeoccasionally.

In accordance with a preferred embodiment of the invention, specializedprioritization rules can be developed and implemented (e.g., programmedinto system 100) to aid in the determination of a priority order. As anexample, a prioritization rule can be developed in which an antennae orsensor can be desensitized to multiple events by “debouncing” theantenna or sensor. For example, where shelf 105 (FIG. 1) is implementedin a retail store environment having a sensor in the form of a customerrequest button, and that button is pressed multiple times within a giventime interval (e.g., 10 seconds), the button can be considered to havebeen pressed only once.

Another prioritization rule may be developed, for example, in which aparticular event (e.g., a customer is detected near a monitored objectby a sensor) will result in assigning the highest priority to any readerantenna associated with that event. The rule may further specify thatthe absence of the event (e.g., the detection of a customer) willincrementally decrease the priority assigned to the associated antennae.

It should be understood that the prioritization cycle and the read cyclemay run at different speeds and not necessarily in sequence, since whilethe antennae may be read in a particular prioritized sequence, it may bepossible or desirable to monitor other sensors at different speeds. Thisprioritization cycle may be run continuously, or periodically. If runperiodically during business hours, the periodic interval may berelatively short. On the other hand, during non-business hours, it maynot be necessary to run the read prioritization cycle, but may bepreferable, for example, simply to read all antennae at the samepriority.

Additional preferred embodiments of the invention include inactivatingor otherwise refraining from interrogating reader antennae. For example,a reader antenna can be inactivated if its position in a priority orderis below a threshold level. In another preferred embodiment of theinvention, a reader antenna can be inactivated in response toinactivation signals (e.g., detecting movement of an identifying tag,proximity of a customer to a reader antenna, proximity of an employee toa reader antenna, proximity of a product to a reader antenna, etc.).Inactivation signals can temporarily inactivate a reading antenna or agroup of reading antennae. For example, a reading antenna can be shutdown if an employee (e.g., wearing an RFID tag) is re-stocking a shelf.

It is to be understood that application of the invention to a specificproblem or environment will be within the capability of one havingordinary skill in the art. Some of the exemplary implementations ofpreferred embodiments of the invention are illustrated by the followingnon-limiting examples.

EXAMPLE

FIGS. 2A and 2B show exemplary method steps of assigning priority toreader antennae, and/or a location associated with a reader antenna, inaccordance with a preferred embodiment of the invention. The methodsteps provide information which is used in the determination of whetherto set the priority of the antenna associated with a given location to apredetermined value (e.g., 1) or to decrease the priority assigned tothe antenna. The method may be implemented by the system shown in FIG. 1or any known means programmed, hard-wired, or otherwise configured toperform the steps described herein.

Antenna Read Prioritization Loop

The priority calculation process for each antenna is initiated in Step200. A determination is made in step 210 as to whether the pushbuttonhas been pushed. If the button has been pushed, the pushbutton priorityvalue for the antenna associated with the location of the pushbutton isset to 1 (step 212). If the button has not been pushed the pushbuttonpriority value of the antenna associated with the location is decreasedby 0.1 (step 215).

In step 220, it is determined if a card (i.e., employee identity card)is present. A magnetic, optical, infrared, RFID or other sensor candetect the presence of a card with an associated identity tag. If a cardis detected (e.g., indicating the presence of an employee restocking ashelf) the card priority for reader antenna associated with the cardsensor is set to 1 (step 222). If a card is not detected, the cardpriority value of the antenna associated with the location is decreasedby 0.1 (step 225).

In step 230, whether the inventory for a location associated with agiven antenna has changed is determined. Inventory can be measured byinterrogating the reader associated with a location (e.g., shelf) todetermine the number of items or objects having associated tags (e.g.,RFID tags). The system can determine the inventory at different timesand compare the inventory results to determine if the inventory haschanged (e.g., increased, decreased, replaced with a different item oritems, etc.). Tithe inventory has changed, the inventory priority forthe associated antenna is set to 1 (step 232). If the inventory has notchanged, the inventory priority for the location associated with theantenna is decreased by 0.03 (step 235).

In step 240, whether the inventory in a first location adjacent to anantenna associated with a second location has changed is determined. Ifthe inventory has changed, then the adjacency priority for readerantenna associated with the second location is set to a predeterminedvalue of 1 (step 242). If the inventory has not changed, the adjacencypriority of the antenna associated with the second location is decreasedby 0.1 (step 245).

In step 250, whether a customer (or another person or object) has beensensed in or near a location associated with a given antenna isdetermined. A customer can be sensed, for example, by any suitablesensor (e.g., optical, infrared, RFID tag, etc.). If a customer is notdetected, then the customer priority is decremented by 0.03 (step 255).If a customer is detected, the system determines whether the customerhas moved outside the range of the antenna or other sensor within apredetermined time interval (e.g., 20 seconds) by, for example,determining the customer's presence at a first time and at a second time(step 251). If the customer is still detected after passage of thepredetermined time interval, the customer priority for the antenna orthe location associated with the antenna is set to 1(step 252). If thecustomer is not detected after the predetermined time interval, thecustomer priority is decreased by 0.03 (step 255).

In step 260, whether the antenna is associated with an area that hasbeen prone to shrinkage (e.g., product loss) is determined. If theantenna associated with a location is prone to shrinkage, then theshrinkage priority for the location is set to 1(step 262). If thelocation associated with the antenna is not associated with shrinkage,then the shrinkage priority is set to 0 (step 272).

In step 270, whether any priorities have been decreased below zero isdetermined. If so, that priority is set to 0 (step 272). When nopriority values are below zero, a read priority for the antenna based,for example, on a priority summation for that antenna of the products ofthe individual priority values and individual weighting factors (step280) is calculated. The individual weighting factors likewise may beadjustable for each antenna.

In step 290, constraints can be enforced. For example, a constraint mayrequire that an antenna can neither be read more frequently than every 2seconds, nor less often than every two hours.

In step 292, information regarding the read priority is updated (e.g.,in table 300) including the new read priority calculated for the antennain question. In this exemplary implementation, read priority table 300provides the priority order for Reader Antennae 151-153 depicted inFIG. 1. The cycle then continues in step 295 by returning to step 200 inFIG. 2A and considering the next antenna.

Read Process Loop

A preferred embodiment of the invention provides an antenna read processloop as shown, for example, in steps 310-330 of FIG. 2B. In thisexemplary implementation, the read process loop determines the pollingsequence of the reader antennae (e.g., Reader Antennae 151-153 ofFIG. 1) according to the priority order as determined, for example, bythe antenna read prioritization loop depicted in steps 200-295. Theantenna read prioritization loop and the read process loop may operateat different speeds.

In step 310, read priority table 200 is consulted to determine whichantenna to read next based on its priority compared to other antennae.In step 320, the antenna with the highest priority is read by theantenna reader (e.g., Reader 140 depicted in FIG. 1). In step 330, thenew information obtained by interrogating the antenna is stored (e.g.,in Database 400). Next, the antenna read process loop cycles back tostep 310 to determine which antenna to read next.

While preferred embodiments of the invention have been described andillustrated, it should be apparent that many modifications to theembodiments and implementations of the invention can be made withoutdeparting from the spirit or scope of the invention. For example,although embodiments and implementations of the invention have beenspecifically illustrated herein as applied to reader antennae for RFIDtags placed on an item, the invention may easily be deployed or embodiedin any form of (RF- or non-RF-based) antennae. Although only a singleAntenna Prioritization System 100 has been illustrated, it should beapparent that there may be a plurality of such Systems 100, and whenimplemented, one or more of the Systems 100 may be connected (directlyor indirectly) with one or more shelves 105 (or other components ormodules).

To the extent the illustrated embodiments have not specified the type ofcommunication medium (or protocol) used to connect the various modules(e.g., shown in FIG. 1), it should be apparent that any knownwired/wireless technology may be used to implement the variousembodiments of the invention (e.g., PCI bus, FireWire®, USB, Internet,intranets, private bulletin boards, individual local or wide areanetworks, proprietary chat rooms, ICQ IRC channels, instant messagingsystems, WAP, Bluetooth, etc.) using real-time or non-real-time systemsalone or in combination.

In accordance with a preferred embodiment, one or more of the same ordifferent user interfaces (e.g., user interface device 130 (FIG. 1)) areprovided as part of (or in conjunction with) the illustrated systems topermit one or more users to interact with the systems. Individual onesof a plurality of devices (e.g., network/stand-alone computers, personaldigital assistants (PDAs), WebTV (or other Internet-only) terminals,set-top boxes, cellular/PCS phones, screen phones, pagers, kiosks, orother known (wired or wireless) communication devices, etc.) maysimilarly be used to execute one or more computer programs (e.g.,universal Internet browser programs, dedicated interface programs, etc.)to allow users to interface with the systems in the manner described.

The modules described herein, particularly those illustrated or inherentin, or apparent from the instant disclosure, may be one or morehardware, software, or hybrid components residing in (or distributedamong) one or more local and/or remote computer or other processingsystems. Although the modules may be shown or described herein asphysically separated components (e.g., controller 110, local database115, user interface 130, reader 140, etc.), it should be readilyapparent that the modules may be omitted, combined or further separatedinto a variety of different components, sharing different resources(including processing units, memory, clock devices, software routines,etc.) as required for the particular implementation of the embodimentsdisclosed (or apparent from the teachings herein). Indeed, even a singlegeneral purpose computer (or other processor-controlled device)executing a program stored on an article of manufacture (e.g., recordingmedium such as a CD-ROM, DVD-ROM, memory cartridge, etc.) to produce thefunctionality referred to herein may be utilized to implement theillustrated embodiments. User interface devices may be any device usedto input and/or output information. The user interface device may beimplemented as a graphical user interface (GUI) containing a display orthe like, or may be a link to other user input/output devices known inthe art.

In addition, database, storage, and other memory units described hereinmay be any one or more of the known storage devices (e.g., Random AccessMemory (RAM), Read Only Memory (ROM), hard disk drive (HDD), floppydrive, zip drive, CD-ROM, DVD-ROM, bubble memory, redundant array ofindependent disks (RAID), storage accessible network (SAN), networkaccessible storage (NAS), etc.), and may also be one or more memorydevices embedded within a controller or CPU, or shared with one or moreof the other components. These units may be disposed locally, remotely,distributed, or otherwise logically or physically configured to practicethe invention.

Moreover, the operational flows and methods shown in (and described withrespect to) FIGS. 2A and 2B can be modified to include additional steps,to change the sequence of the individual steps as well as combining (orsubdividing), simultaneously running, omitting, or otherwise modifyingthe individual steps shown and described in accordance with theinvention. Numerous alternative methods may be employed to produce theoutcomes described with respect to the preferred embodiments illustratedabove or equivalent outcomes. It should be apparent to those of ordinaryskill in the art that method steps inherent or apparent from thedisclosure herein of various physical systems (or components thereof)may be implemented using the disclosed (or any other systems) inaccordance with the invention. Detailed descriptions of such methodsteps therefore need not be provided herein.

It is to be understood therefore that the invention is not limited tothe particular embodiments disclosed (or apparent from the disclosure)herein, but only limited by the claims appended hereto.

1. A method of operating a plurality of reader antennae, comprising:determining a priority order of the plurality of reader antennae; andsetting a polling sequence for reading the plurality of reader antennaeaccording to the priority order determined in said determining step. 2.The method of claim 1, wherein said determining step further comprises:assigning a preference level to each of the plurality of readerantennae; and deriving a priority order based on the preference levelsassigned to each of the plurality of reader antennae.
 3. The method ofclaim 2, wherein said assigning step further comprises assigning a firstreader antenna having a higher preference level with a higher prioritythan at least a second reader antenna having a lower priority.
 4. Themethod of claim 2, further comprising the step of reading the pluralityof reader antennae according to the priority order determined in saiddetermining step.
 5. The method of claim 4, wherein said reading stepcomprises reading more frequently a first reader antennae that has ahigher preference level compared to a second reader antennae.
 6. Themethod of claim 2, wherein said assigning step comprises randomlyassigning a preference level to each of the plurality of readerantennae.
 7. The method of claim 2, further comprising the step ofinactivating a reader antenna.
 8. The method of claim 7, wherein saidinactivating step comprises inactivating a reader antenna in response toone of the group of: detecting movement of an identifying tag; proximityof a customer to a reader antenna; proximity of an employee to a readerantenna; and proximity of a product to a reader antenna.
 9. The methodof claim 1, wherein said determining step comprises assigning thepriority order such that the plurality of reader antennae can be read atan equal frequency.
 10. The method of claim 2, wherein said assigningstep comprises assigning preference levels based on products detected byeach of the plurality of reader antennae.
 11. The method of claim 10,wherein said assigning step comprises assigning a first reader antennathat detects a larger number of products with a higher preference levelthan at least a second reader antenna that detects a smaller number ofproducts.
 12. The method of claim 2, wherein said assigning stepcomprises assigning preference levels according to a preference factorselected from the group consisting of: movement of an identifying tagassociated with a reader antenna; proximity of a customer to a readerantenna; proximity of an employee to a reader antenna; and proximity ofa product to a reader antenna.
 13. The method of claim 2, wherein saidassigning step comprises assigning preference levels based on input datafrom a device selected from the group of: a computer server; a computerworkstation; a handheld device; a telephone; and a wireless device. 14.The method of claim 2, wherein said assigning step comprises assigningpreference levels based on input data from a sensor.
 15. The method ofclaim 14, wherein said assigning step comprises assigning preferencelevels based on input data from a sensor selected from the groupconsisting of: an optical sensor; a vibration sensor; an audio sensor; apressure sensor; and a pushbutton sensor.
 16. A method of adjusting thepriority order of a polling sequence for a plurality of RFID antennae,the method comprising: providing a plurality of product supportstructures, each product support structure associated with at least oneRFID reader antenna; placing a plurality of products on at least one ofthe product support structures, each of the plurality of productsassociated with an RFID tag; identifying the location of each of theplurality of products by detecting the associated RFID tags with theplurality of RFID reader antennae; assigning a priority order to theplurality of RFID antennae, the priority order determined by assigning apreference level to each of the plurality of RFID antennae; andassigning a polling sequence for reading the plurality of RFID readerantennae according to the priority order.
 17. The method of claim 16,wherein said assigning a priority comprises assigning preference levelsbased on input data from a sensor.
 18. The method of claim 16, whereinsaid assigning a priority comprises assigning preference levels based onproducts detected by each of the plurality of RFID reader antennae. 19.The method of claim 10, wherein said assigning a priority comprisesassigning a first RFID reader antenna that detects a larger number ofproducts with a higher preference level than at least a second RFIDreader antenna that detects a smaller number of products.
 20. An antennaprioritization system for use in prioritizing the reading of a pluralityof reader antennae, the system comprising: a controller device fordetermining a priority order of the plurality of RFID antennae, and forsetting a polling sequence for reading ones of the plurality of RFIDreader antennae according to the priority order; and a reader forreading ones of the plurality of reader antennae in accordance with thepolling sequence.